class Program
    {
        static void Main(string[] args)
        {
            string[] str = Console.ReadLine().Split(' ');
            if (long.Parse(str[0]) > long.Parse(str[1]))
            {
                Console.WriteLine(2000000000-long.Parse(str[0]));
            }
            else
            {
                Console.WriteLine(long.Parse(str[0])-1);
            }
        }
    }